2018-19 Section 7-Neoplastic and Inflammatory Diseases of the Head and Neck eBook

RR (95% CI)

Non-diagnostic Strickland

0.60 (0.23, 1.53) 0.94 (0.53, 1.68) 1.00 (0.16, 6.45) 0.84 (0.53, 1.36) 0.41 (0.19, 0.86) 0.63 (0.39, 1.01) 0.67 (0.20, 2.24) 0.56 (0.38, 0.83) 0.55 (0.35, 0.87) 0.56 (0.44, 0.73) 0.87 (0.44, 1.71) 0.59 (0.47, 0.72) 0.82 (0.58, 1.18) 0.54 (0.41, 0.73) 0.89 (0.49, 1.62) 0.70 (0.51, 0.97) 0.52 (0.42, 0.66) 0.72 (0.62, 0.82) 0.79 (0.58, 1.08) 0.66 (0.53, 0.83) 0.95 (0.91, 0.99) 0.97 (0.95, 0.99) 0.87 (0.77, 0.99) 0.96 (0.93, 0.99)

Faquin Layfield Subtotal Benign Strickland Faquin Layfield Subtotal FLUS Strickland Faquin Layfield Subtotal

Follicular neoplasm Strickland

Fig. 1. Forest plot of the relative risk of ma- lignancy. It shows the relative risk of malig- nancy for each category, as determined by the Bethesda System for Reporting Thyroid Cytology. Relative risk is defined as the rate of malignancy using the classification non- invasive follicular variant of papillary thy- roid carcinoma (NIFTP) relative to the ma- lignancy rate without using NIFTP. The boxes indicate point estimates for each study. The size of the box is proportional to the weight given to each study in the cate- gory average (subtotal). The whiskers indi- cate the 95%CI for the study estimate. Dia- monds indicate the estimated average. The length of the diamond is the 95% CI for the combined average. FLUS, follicular lesion of undetermined significance; RR, relative risk.

Faquin Layfield Subtotal

Suspicious for malignancy Strickland

Faquin Layfield Subtotal Malignant Strickland Faquin Layfield Subtotal

0.155

1

6.45

as “AUS/FLUS,” and 2% as “malignant.” They found good correlation between nuclear features in cytologic specimens and histopathologic diagnoses. The nuclear features of NIFTP in their study of 96 NIFTPs were sig- nificantly different than those seen in benign nodules, but not distinct from those characteristic of invasive follicular variant papillary thyroid carcinomas [14] . They conclud- ed that most NIFTP nodules were classified in the inde- terminate categories of the TBSRTC system [14] . Such a categorization of NIFTP (a benign lesion) into the inde- terminate categories would undoubtedly impact the ma- lignancy risk of these categories, as originally defined by the Bethesda system. Howitt et al. [13] reported similar

A number of authors have investigated the cytologic features and subsequent cytologic categorization of NIFTP lesions undergoing FNA. Maletta et al. [14] rec- ognized that acceptance of NIFTP neoplasms as benign would impact significantly the risk of malignancy asso- ciated with the currently used diagnostic categories of TBSRTC. In a study of 96 histologically confirmed NIFTPs, they analyzed the FNA cytologic features and determined how the main nuclear features correlated in cytologic and histologic samples. Their blind review of FNA specimens from NIFTP nodules demonstrated that 56% of these neoplasms would be categorized as “follicu- lar neoplasms,” 27% as “suspicious for malignancy,” 15%

Malignancy Risk and NIFTP

Acta Cytologica 2017;61:187–193 DOI: 10.1159/000469654

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